const Base64 = {
    // private property
    _keyStr: "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",
  
    // public method for encoding
  
    encode: function(input:string):string {
      let output = "";
  
      let chr1,
        chr2,
        chr3,
        enc1,
        enc2,
        enc3,
        enc4;
  
      let i = 0;
  
      input = Base64._utf8_encode(input);
  
      while (i < input.length) {
  
        chr1 = input.charCodeAt(i++);
  
        chr2 = input.charCodeAt(i++);
  
        chr3 = input.charCodeAt(i++);
  
        enc1 = chr1 >> 2;
  
        enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
  
        enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
        enc4 = chr3 & 63;
  
        if (isNaN(chr2)) {
  
          enc3 = enc4 = 64;
  
        } else if (isNaN(chr3)) {
  
          enc4 = 64;
  
        }
  
        output = output + this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) + this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
  
      }
  
      return output;
  
    },
  
    // public method for decoding
  
    decode: function(input:string):string {
  
      let output = "";
  
      let chr1,
        chr2,
        chr3;
  
      let enc1,
        enc2,
        enc3,
        enc4;
  
      let i = 0;
  
      input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
  
      while (i < input.length) {
  
        enc1 = this._keyStr.indexOf(input.charAt(i++));
  
        enc2 = this._keyStr.indexOf(input.charAt(i++));
  
        enc3 = this._keyStr.indexOf(input.charAt(i++));
  
        enc4 = this._keyStr.indexOf(input.charAt(i++));
  
        chr1 = (enc1 << 2) | (enc2 >> 4);
  
        chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
  
        chr3 = ((enc3 & 3) << 6) | enc4;
  
        output = output + String.fromCharCode(chr1);
  
        if (enc3 != 64) {
  
          output = output + String.fromCharCode(chr2);
  
        }
  
        if (enc4 != 64) {
  
          output = output + String.fromCharCode(chr3);
  
        }
  
      }
  
      output = Base64._utf8_decode(output);
  
      return output;
  
    },
  
    // private method for UTF-8 encoding
  
    _utf8_encode: function(string:string) {
  
      string = string.replace(/\r\n/g, "\n");
  
      let utftext = "";
  
      for (let n = 0; n < string.length; n++) {
  
        const c = string.charCodeAt(n);
  
        if (c < 128) {
  
          utftext += String.fromCharCode(c);
  
        } else if ((c > 127) && (c < 2048)) {
  
          utftext += String.fromCharCode((c >> 6) | 192);
  
          utftext += String.fromCharCode((c & 63) | 128);
  
        } else {
  
          utftext += String.fromCharCode((c >> 12) | 224);
  
          utftext += String.fromCharCode(((c >> 6) & 63) | 128);
  
          utftext += String.fromCharCode((c & 63) | 128);
  
        }
  
      }
  
      return utftext;
  
    },
  
    // private method for UTF-8 decoding
  
    _utf8_decode: function(utftext:string) {
  
      let string = "";
  
      let i = 0;
  
      let c =0, c3 =0, c2 = 0;
  
      while (i < utftext.length) {
  
        c = utftext.charCodeAt(i);
  
        if (c < 128) {
  
          string += String.fromCharCode(c);
  
          i++;
  
        } else if ((c > 191) && (c < 224)) {
  
          c2 = utftext.charCodeAt(i + 1);
  
          string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
  
          i += 2;
  
        } else {
  
          c2 = utftext.charCodeAt(i + 1);
  
          c3 = utftext.charCodeAt(i + 2);
  
          string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
  
          i += 3;
  
        }
  
      }
  
      return string;
  
    }
  
  }
  
  export default Base64